The objectives of this proposed research are to design and synthesize sulfur containing compounds that stimulate detoxifying enzymes as defenses against carcinogens. The long-term goal is to develop these compounds into cancer chemopreventive agents for human use. To test the feasibility of the new compounds as potential inhibitors of chemically induced carcinogenesis a number of rapid screening tests will be used. The inhibition of DNA methylation of precancerous lesions in the colon will be determined. The results will indicate whether the new compounds may be used as chemopreventive agents in the lung and colon respectively.